According to scientists, ferrihydrite-enriched soil has the potential to reduce the concentration of arsenic and uranium—elements that pose health risks to consumers.
Arsenic, uranium, and other trace elements naturally occur in the topsoil throughout the Corn Belt of the Midwestern United States, including the state of Nebraska.
Crops grown in soil with high levels of these trace elements can absorb them through their roots. These elements can inhibit plant growth and threaten the health of those who regularly consume them.
Adding ferrihydrite to irrigation water can reduce the concentration of harmful elements.
Researchers Arindam Malakar, Chittaranjan Ray, and their colleagues at the University of Nebraska – Lincoln have investigated whether ferrihydrite can help address this issue. Ferrihydrite is a nano-mineral found in soil, but it is also used for treating groundwater and drinking water.
As part of a greenhouse experiment using soil from the university’s Panhandle Research and Extension Center, the team planted corn in three types of soil: one without ferrihydrite, another with 0.05% ferrihydrite, and a third with 0.10% of the mineral.
After irrigating the soil with water enhanced with arsenic and uranium, the researchers monitored the growth of the corn plants. They also tracked the concentrations of trace elements in the water surrounding the plant roots.
The research team found that ferrihydrite-enriched soil can reduce the concentrations of arsenic and uranium by approximately 20%. This type of soil also appeared to reduce nitrate leaching by about 30% to 50%.
Nitrate is essential for crop growth but can cause health issues when it leaches into groundwater. Meanwhile, the soil’s water retention capacity increased from about 13% without ferrihydrite to around 17% with it.
Importantly, corn also benefited from this type of soil. Plants grown in ferrihydrite-rich soil were taller and produced approximately 12% to 15% more biomass. Additionally, the plants were able to synthesize more chlorophyll and produced seeds containing nearly double the amount of iron.
The researchers noted that conducting similar experiments under real field conditions, rather than in a greenhouse, would be necessary to validate the findings of the study.
Initial findings suggest that even small amounts of ferrihydrite added to irrigation water can limit the concentration of harmful elements while promoting crop growth and nutrient absorption.
